FIGS. 1 and 2 illustrate a conventional coil 10 having a pair of spaced tube sheet end plates 11 and 12. Plural fins 13 are oriented between the tube sheet end plates 11 and 12. Plural and axially aligned sets of holes are provided in each of the tube sheet end plates 11 and 12 and the fins 13 and are adapted to receive therein the legs 14 of U-shaped hairpin tubes 16. If desired, a tube expander can be utilized in expanding the diameter of the legs 14 of each of the hairpin tubes to effect a fixed securement of each hairpin tube to the respective tube sheet end plate 11, 12 and the plural fins 13 oriented therebetween. The open ends 19 of each of the hairpin tubes 16 can be in a staggered array as illustrated in FIG. 1 or an in-line pattern (not illustrated). The illustration in FIG. 2 is of the staggered pattern array. In this particular embodiment, the open end of the U-shaped hairpin tubes are each equally spaced from the mutually adjacent open ends of other U-shaped hairpin tubes.
Heretofore, assembly workers have been utilized in placing return bends (also known as "U" bends) 17 into selected ones of the open ends of the hairpin shaped tubes 16 in accordance with a particular work order. For example, the assembly worker might install the return bends 17 in the array illustrated in FIG. 2. This task would involve the assembly worker carefully aligning the end segments 18 of a particular return bend 17 with the open ends 19 of a hairpin tube 16 and taking a hammer and slightly tapping the return bend into place. While many assembly workers can work at a very rapid pace, pattern errors are sometimes made which necessitates a disassembly of the return bends 17 and a reassembly thereof in accordance with the correct pattern.
Accordingly, it is an object of the present invention to provide an assembly device enabling an automated assembly of the return bends to the open ends of the hairpin tubes incorporated into a coil construction to enable a reduction in the labor force required to perform the desired task.
It is a further object of the invention to provide an automated assembly device, as aforesaid, which is rapid in its operation and consistently performs the assembly task in the desired pattern. It is a further object of the invention to provide an assembly device, as aforesaid, utilizing only a single worker to place workpieces or coils having no return bends installed into a specific location thereon and then activate the assembly device to have all of the return bends automatically inserted in the desired pattern into the open ends of the hairpin tubes.
It is a further object of the invention to provide an assembly device, as aforesaid, which is durable in its construction and is capable of rapidly inserting return bends into the open ends of hairpin tubes of a coil construction in accordance with the desired pattern.
It is a further object of the invention to provide an assembly device, as aforesaid, which performs the task of the inserting of return bends into the appropriate ones of the open ends of the hairpin tubes without damaging the end segments of the return bends or the perimeter of the open ends of the hairpin tubes so that upon a soldering of the return bends to the hairpin tubes, leakage will be prevented.